This invention relates to enclosures, specifically for printed circuit boards.
Circuits on printed circuit boards often need to be enclosed to prevent physical damage, to keep out dust and moisture, and to eliminate electric shock and short circuit hazards. The prior art in enclosures for printed circuit boards consists of a large variety of metal and plastic boxes designed to support and totally contain the printed circuit board. Wires, cables, and pressure/vacuum tubing attached to the printed circuit board must either pass through the walls of the enclosure or terminate at input/output devices such as switches, displays, and controls mounted in the walls of the enclosure. This type of enclosure for printed circuit boards has the following deficiencies:
(a) Design of penetrations into an enclosure for egress of cables or for installing input/output devices adds significant engineering cost to the enclosure.
(b) Machining penetrations into an enclosure and installation of feed-through fittings and input/output devices adds significant manufacturing cost to the enclosure.
(c) Compression feed-through fittings used on the enclosure for cable egress cannot seal effectively around groups of individual wires.
(d) Feed-through connectors on the enclosure are redundant when connectors are also located on the printed circuit board.
(e) The enclosure becomes essentially part of the wiring harness and cannot be replaced or moved without considerable effort.
(f) Removing the lid of the enclosure allows only very restricted access, further hampered by enclosed cables, to one side of the circuit board for test, modification, or repair.
(g) The enclosure must be oversized to contain relief bends in cables and tubing, to provide working room for attaching terminals and connectors, and to contain extra cable or tubing for slack if the card is to be removed from the enclosure while operating for access during test, modification, or repair.
There is a need for an improved enclosure that protects the circuits on a printed circuit board without the above deficiencies.